Public displays of affection (PDA) are acts of physical intimacy in the view of others. What is considered to be an acceptable display of affection varies with respect to culture and context.

Physical intimacy is sensuous proximity or touching. It is an act or reaction, such as an expression of feelings, between people. Examples of physical intimacy include being inside someone's personal space, holding hands, hugging, kissing, caressing and sexual activity. Physical intimacy can often convey the real meaning or intention of an interaction in a way that accompanying speech cannot do. Physical intimacy can be exchanged between any people but as it is often used to communicate positive and intimate feelings, it most often occurs in people who have a preexisting relationship, whether familial, platonic or romantic, with romantic relationships having increased physical intimacy. Several forms of romantic touch have been noted including holding hands, hugging, kissing, cuddling, as well as caressing and massaging. Physical affection is highly correlated with overall relationship and partner satisfaction.